tailieunhanh - Báo cáo khoa học: "Leaf gas exchange and carbohydrate concentrations in Pinus pinaster plants subjected to elevated CO 2 and a soil drying cycle"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Leaf gas exchange and carbohydrate concentrations in Pinus pinaster plants subjected to elevated CO 2 and a soil drying cycle. | 71 Ann. For. Sci. 56 1999 71-76 Inra Elsevier Paris Note Leaf gas exchange and carbohydrate concentrations in Pinus pinaster plants subjected to elevated CO2 and a soil drying cycle Catherine Picon-Cochard Jean-Marc Guehl Unite de recherches en écophysiologie forestiere Équipe bioclimatologie-écophysiologie Inra Nancy 54280 Champenoux France Received 15 December 1997 accepted 31 March 1998 Abstract - Plants of maritime pine Pinus pinaster Ait. were acclimated for 2 years under ambient 350 pmol moF1 and elevated 700 pmol moF1 co concentrations CO2 . In the summer of the second growing season the plants were subjected to a soil drying cycle for 6 days. Drought reduced plant transpiration rate and net co assimilation rate A by about 80 . Elevated CO induced a substantial increase of A 105 and 229 in well-watered and in draughted plants respectively and of the needle starch 145 and sucrose 20 concentrations whatever the watering regime. Drought did not significantly affect starch and sucrose concentrations while hexose concentrations were slightly increased in the most severe drought condition predawn water potential value equal to MPa . The stimulating effect of elevated CO on A was maintained along the drying cycle whereas no significant co effect was observed on the soluble carbohydrate concentration. These compounds did not contribute to an enhancement of osmotic adjustment under elevated CO2 in p. pinaster. Inra Elsevier Paris. elevated CO2 drought leaf gas exchange carbohydrate Pinus pinaster Resume - Echanges gazeux foliaires et concentrations en glucides de plants de Pinus pinaster soumis à un enrichissement en CO2 de 1 air et à un dessèchement du sol. Des semis de pin maritime Pinus pinaster Ait. ont été acclimates pendant deux ans à 350 et à 700 pmol moF1 de concentrations en CO2 atmosphérique CO . Au cours de 1 été de la deuxième saison de croissance les plants ont été soumis à un dessèchement du sol pendant 6 j. La sécheresse a réduit d environ 80 la .